1 files changed, 42 insertions, 0 deletions
diff --git a/scripts/thread_instr.py b/scripts/thread_instr.py
new file mode 100755
index 0000000..846d27f
--- /dev/null
+++ b/scripts/thread_instr.py
@@ -0,0 +1,42 @@
+#!/usr/bin/env python3
+"""User-space instructions per thread name over an interval (perf stat --per-thread) —
+a load-independent cost measure: CPU % swings with other work on the machine and
+clock speed, retired instructions don't (smoke_run.sh step `instr:<s>`).
+
+Usage: scripts/thread_instr.py PID SECONDS
+"""
+import re
+import subprocess
+import sys
+from collections import defaultdict
+
+
+def parse(text):
+    """{thread name: instructions} from `perf stat --per-thread -x,` output."""
+    out = defaultdict(int)
+    for line in text.splitlines():
+        parts = line.split(",")
+        if len(parts) < 4 or "instructions" not in parts[3]:
+            continue
+        try:
+            count = int(parts[1])
+        except ValueError:
+            continue  # <not counted>
+        out[re.sub(r"-\d+$", "", parts[0].strip())] += count
+    return out
+
+
+def main():
+    pid, seconds = sys.argv[1], float(sys.argv[2])
+    res = subprocess.run(["perf", "stat", "--per-thread", "-x,", "-e", "instructions:u", "-p", pid,
+                          "--", "sleep", str(seconds)], capture_output=True, text=True)
+    counts = parse(res.stderr)
+    total = sum(counts.values())
+    print(f"instr: {total / seconds / 1e6:.0f} M/s total over {seconds:g}s")
+    for name, n in sorted(counts.items(), key=lambda kv: -kv[1])[:8]:
+        if n / seconds >= 1e6:
+            print(f"  {n / seconds / 1e6:7.0f} M/s  {name}")
+
+
+if __name__ == "__main__":
+    main()